Biodiversity & Conservation

Antedon spp., solitary ascidians and fine hydroids on sheltered circalittoral rock



Image Keith Hiscock - Circalittoral rock with Antedon bifida, hydroids and occasional solitary sea squirts. Image width ca 60 cm.
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Distribution map

CR.SCR.BrAs.AntAsH recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats

Text page icon Habitat description

Map icon Distribution of biotope in Britain and Ireland Recorded from the west coast of Scotland and Scottish sea lochs.
National importance Uncommon

Text page icon Description of biotope

For a full description of this biotope including characterizing species, distribution, survey information and references visit JNCC

Typically found in sheltered parts of sea lochs which might be subject to slight tidal currents. No one phyla or species dominates the rock but the most conspicuous comprise featherstars (Antedon bifida, Antedon petasus and more rarely Leptometra celtica), solitary ascidians (e.g. Ascidia mentula) and hydroids (Kirchenpaueria pinnata, Halecium halecinum and Bougainvillia ramosa). In the sea lochs, where the three species of featherstar are found at the same site Antedon petasus is often the more abundant featherstar in deeper water whereas Antedon bifida tends to dominate the shallower regions. Leptometra celtica tends to occur in deep water and is also found on rocks on mud plains. Caryophyllia smithii, serpulid worms, Balanus balanus, Munida rugosa, brachiopods, some brittlestars, and algal crusts are all typically present. Crustose sponges such as Hymedesmia paupertas may occur on vertical faces. In deep water at some sites in sea lochs Mycale lingua and Leptometra celtica are found on upward facing rock. This biotope has some overlaps with the solitary ascidian biotopes (As) although these tend to occur is slightly more sheltered conditions with little or no tidal flow. (Information taken from the Marine Biotope Classification for Britain and Ireland, Version 97.06: Connor et al., 1997a, b).

Additional information icon Additional information

This review can be cited as follows:

Hill, J.M. 2001. Antedon spp., solitary ascidians and fine hydroids on sheltered circalittoral rock. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 26/11/2015]. Available from: <>